What Is DEF and Do I Need It? A Plain-Language Guide for Indiana Drivers and Fleet Operators
Diesel Exhaust Fluid (DEF) is a non-toxic fluid used by many newer diesel engines to reduce harmful emissions. If your diesel truck or equipment is equipped with a Selective Catalytic Reduction (SCR) system, it likely requires DEF to operate properly. Many diesel owners first hear about DEF when a dashboard warning light appears or while […]








